Fair Value Measurement - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($) contract	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	$ 58.2		$ 57.4
Trading securities	12.7		10.2
Purchase of trading securities related to deferred compensation plans	1.9	$ 1.2
Proceeds from securities sold	$ 0.3	$ 1.1
Number of foreign exchange contracts held (in contracts) | contract	55
Long-term debt, fair value	$ 1,024.3		1,017.8
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0.0		0.0
Trading securities	12.7		$ 10.2
Forward exchange contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, notional amount	$ 40.4